DomainBacteria

DomainArchaea

DomainEukarya

Common ancestor

Tutorial: Plants

Kingdom: Plants Domain Eukarya

The first plants For more than 3 billion years, Earth’s terrestrial surface was lifeless

life evolved in the seas 1st photosynthetic plant organisms were aquatic green algae

(charophytes/chlorophytes)

special adaptations for life on dry land protection from drying = desiccation

waxy cuticle gas & water vapor exchange (through cuticle)

stomates water & nutrient conducting systems

xylem & phloem protection for embryo

seeds

Plant Diversity

Bryophytesnon-vascularland plants

Pteridophytesseedless

vascular plants

Gymnospermpollen &

“naked” seeds

Angiospermflowers & fruit

seed plants

vascular plants

mosses fernsconifers flowering plants

colonization of land

non-vascular plants

seedless plants

Plant Classification

Bryophytes Pteridophytes

Tracheophytes

Gymnosperm

Conifer Angiosperm

Non-vascular Vascular Vascular Vascular

seedless seedless seeds seeds

Spores &

Haploid Gameotophyte

Spores &

Haploid Gameotophyte Cones - naked seeds Flowers - fruit w/ seeds

Swimming sperm Swimming sperm Pollen & Seeds Pollen & Seeds

Mosses, liverworts Ferns Pine, Spruce, Redwood Lily, Maple, Oak, Rose

Vascular tissue Transports materials in roots, stems & leaves Xylem

carry water & minerals up from roots

tube-shaped dead cells only their walls provide a system

of microscopic water pipes

Phloem carry nutrients throughout plant

sugars (sucrose), amino acids… tube-shaped living cells

Alternation of generations Fern gametophyte (1n)

small haploid plant which produces gametes homospory: male & female on same plant

archegonia

antheridia

Anther

FilamentStamen

StigmaStyleOvary

Carpel

Sepal

Petal

Ovule

sepalspetals

Flower Modified shoot with 4 rings

of modified leaves sepals petals stamens

male carpel

female stamens

carpel

Fertilization in flowering plants

Double fertilization 2 sperm from pollen

1 sperm fertilizes egg = diploid zygote (n+n = 2n)

1 sperm fuses with 2 polar nuclei to form endosperm (n+2n = 3n)

endosperm = food tissue in seed

Polarnuclei

Eggcell

Pollengrains

Seed & Plant embryo

Seed offers… protection for embryo stored nutrients for

growth of embryo Embyonic leaves,

shoot, and root

seed coat

endosperm

cotyledons

embryo

cotyledons = “seed” leaves,first leaves of new plantcotyledons = “seed” leaves,first leaves of new plant

epicotyl

radicle

endosperm = “food” storage for developing plant until it can begin making its own.

endosperm = “food” storage for developing plant until it can begin making its own.

Preventing self-pollination Various mechanisms

stamens & carpels may mature at different times arranged so that animal pollinator won’t transfer pollen

from anthers to stigma of same flowerbiochemical self-incompatibility = block pollen tube growth

Co-evolution: flowers & pollinators

How a bee sees a flower…insects see UV light = a bulls-eye to the nectar

Guard Cells

1

5

4

3

89

6

2

7

1

2

3

4

5

6

7

8

9

Stoma

Palisade Layer

Spongy Layer

Upper Epidermis

Cuticle

Lower Epidermis

Xylem

Phloem

Leaf Anatomy (structure)

Root Structure

Epidermis: skin covering

Root Cap - at the tip of the root, produces a slimy substance

Vascularization:

1. Phloem - food to the floor

PhloemXylem

Root Hairs: extend out from the root

2. Xylem - water up

Rise of water in a tree by bulk flow Transpiration pull

adhesion & cohesion H bonding

brings water & minerals to shoot

Water potential high in soil

low in leaves Root pressure push

due to flow of H2O from soil to root cells

upward push of xylem sap

Plant ResponsesTropism - growth in response to a stimulus

1. Phototropism - • change in plant growth caused by light

(plants bend toward light)

3. Gravitropism - • change in plant growth in response to the direction of gravity (plants bend up, away from gravity)

4. Thigmotropism - • growth in response to touch or contact (plants bend along or around objects)

2. Photoperiodism- • developmental responses of plants to the relative lengths of light and dark periods.

Plant Responses - Seasonal changes in leaves

1. Evergreen - they gradually shed some of their leaves    

         throughout the year, and as a result, maintain leaves year-round.

2. Deciduous - lose all their leaves at once, usually for winter.

What classification of plants are they? In what biome would you find them?

accessory pigments: xanthraphyll (yellow) and carotenoids (reds and oranges)

cannot transfer light energy directly to the photosynthetic pathway, they must pass their absorbed energy to chlorophyll. If chlorophyll is rendered ineffective, the energy does not get passed on, therefore, food is not being made, and consequently the leaves will die.

As chlorophyll productiveness declines with the cool temperatures of autumn, the dominant green color fades, displaying the yellows, oranges, and reds of the accessory pigments.

Colors of the rainbow: R O Y G B I V

Abscission - shedding of leaves, fruits, flowersSenscence - dieing off of the plant or plant parts